The disclosures herein relate generally to portable computers and more particularly to a two-piece flex circuit bobbin for use therewith.
In portable computers, the LCD screen is provided on a hinged top which is rotatably mounted on a base. Electrical connections are required between the base and top. These electrical connections must transition through the hinged connection between the base and the top. To accomplish this, a flex circuit with multiple circuit traces is used.
One end of the flex circuit is connected to the motherboard in the base. The other end includes connections to the LCD screen, the inverter board for the back light, and several LED displays which indicate the operational status of the computer including, for example, power on, whether the power is AC or battery-power, whether the battery is low, and whether the hard drive or a floppy drive are in use. Physically, the flex circuit comprises a circuit trace layer and a copper clad substrate EMI shielding layer disposed on either side of the circuit layer. The thickness of these layers is about 0.030 inches.
The flex circuit is adhered to and wrapped around a bobbin located adjacent the area of the hinged connector. The bobbin is a tubular device, circular in cross-section. A protruding terminal edge of the flex circuit is adhered to an outer arcuate surface of the bobbin. The flex circuit is wrapped around the bobbin sufficiently to overlappingly engage the edge prior to installation of the bobbin adjacent the hinged connector. Repeated opening and closing of the hinged top wraps and unwraps the flex circuit around the bobbin. This motion exposes the overlapping portion of the flex circuit into repeated engagement with the edge, which eventually wears and works the flex circuit until one or more of the circuit traces fracture or fail.
Therefore, what is needed is a flex circuit and bobbin combination which can be repeatedly wrapped and unwrapped due to opening and closing the top of the portable computer in a manner which reduces wear and improves the life and reliability of the flex circuit.